Improved Isolation Barrier

ABSTRACT

An apparatus ( 10 ) and method for securing a tubular ( 12 ) within another tubular or borehole ( 80 ), creating a seal across an annulus in a wellbore ( 80 ), and centralising or anchoring tubing within a wellbore. A sleeve ( 14 ) is arranged on a tubular body ( 12 ) to create a chamber ( 16 ) therebetween. A port ( 18 ) provides fluid access through the body to the chamber. The chamber is filled with a swellable material ( 20 ). Thus the sleeve can be morphed to secure it to a well bore wall by the use of fluid pressure and an activated swellable material, the swellable material being used to support the sleeve to maintain a seal between the sleeve and well bore wall to form an isolation barrier.

The present invention relates to an apparatus and method for securing atubular within another tubular or borehole, creating a seal across anannulus in a well bore, and centralising or anchoring tubing within awellbore. In particular, though not exclusively, the invention relatesto morphing a sleeve to secure it to a well bore wall by the use of afluid pressure and an activated swellable material, the swellablematerial being used to support the sleeve to maintain a seal between thesleeve and well bore wall to form an isolation barrier.

In the exploration and production of oil and gas wells, packers aretypically used to isolate one section of a downhole annulus from anothersection of the downhole annulus. The annulus may be between tubularmembers, such as a liner, mandrel, production tubing and casing orbetween a tubular member, typically casing, and the wall of an openborehole. These packers are carried into the well on tubing and at thedesired location, elastomeric seals are urged radially outwards orelastomeric bladders are inflated to cross the annulus and create a sealwith the outer generally cylindrical structure i.e. another tubularmember or the borehole wall.

Another class of packers are swellable packers where a swellableelastomer is wrapped on a tubular body. Metal end rings may be locatedon the body to protect the swellable elastomer on run-in and preventlongitudinal extrusion of the elastomer so that swelling increases theouter original diameter of the swellable elastomer. The packers aresimply run to depth on a tubing string and allowed to swell beforeproduction or injection operations begin. An advantage of swellablepackers is their simplicity with no moving parts, but they have somemajor disadvantages. As the swellable material is exposed on the outersurface of the tubular body, fluid in the annulus will flow over theelastomer during run-in and risk early activation. As these swellableelastomers are activated by oil and/or water and water based fluids i.e.common oil field fluids, the well bore must be kept clear of theactivating fluid until such time as the packer is in position andrequires to be set. Additionally, these packers use the swellableelastomer to create the seal with the inner surface of the largerdiameter cylindrical structure. Uniform swelling is assumed so thatthese packers are best used when a seal to another tubular is required.For open hole deployment, as swelling is achieved by absorption ordiffusion of the fluid into the swellable material, when a seal is madeat a first point on the borehole wall, sections of the outer surface ofthe elastomer may not be exposed to the fluid and thus swelling can benon-homogenous risking areas where a seal is not formed.

All these prior art packers have the same disadvantage in that they usean elastomer to create the seal against the outer generally cylindricalstructure. Consequently, the elastomer must be exposed to well fluids inuse and therefore they cannot be used where corrosive fluids arepresent, for example in chemical injection applications.

As a result, metal seals have been developed, where a tubular metalmember is run in the well and at the desired location, an expander toolis run through the member. The expander tool typically has a forwardcone with a body whose diameter is sized to the generally cylindricalstructure so that the metal member is expanded to contact and sealagainst the cylindrical structure. These so-called expanded sleeves havean internal surface which, when expanded, is cylindrical and matches theprofile of the expander tool. These sleeves work well in creating anannular seal between tubular members but can have problems in sealingagainst the irregular surface of an open borehole.

The present applicants have developed a technology where a metal sleeveis forced radially outwardly by the use of fluid pressure actingdirectly on the sleeve. Sufficient hydraulic fluid pressure is appliedto move the sleeve radially outwards and cause the sleeve to morphitself onto the generally cylindrical structure. The sleeve undergoesplastic deformation and, if morphed to a generally cylindrical metalstructure, the metal structure will undergo elastic deformation toexpand by a small percentage as contact is made. When the pressure isreleased the metal structure returns to its original dimensions and willcreate a seal against the plastically deformed sleeve. During themorphing process, both the inner and outer surfaces of the sleeve willtake up the shape of the surface of the wall of the cylindricalstructure. This morphed isolation barrier is therefore ideally suitedfor creating a seal against an irregular borehole wall.

Such a morphed isolation barrier is disclosed in U.S. Pat. No.7,306,033, which is incorporated herein by reference. An application ofthe morphed isolation barrier for FRAC operations is disclosed inUS2012/0125619, which is incorporated herein by reference. Typically,the sleeve is mounted around a supporting tubular body, being sealed ateach end of the sleeve to create a chamber between the inner surface ofthe sleeve and the outer surface of the body. A port is arranged throughthe body so that fluid can be pumped into the chamber from thethroughbore of the body.

In use, the pressure of fluid in the throughbore is increasedsufficiently to enter the chamber and force the sleeve radiallyoutwardly to morph to the generally cylindrical structure. Sufficientpressure has been applied when there is no return of fluid up theannulus which verifies that a seal has been achieved.

There are a number of difficulties in expanding a sleeve in this manner.Initially, sufficient pressure must be generated at the location of theport. This is done by increasing fluid pressure at surface and it isdifficult to predict what the pressure will be at what may be asignificant depth in the well where the sleeve is positioned.Alternatively, a setting tool can be run but this requires interventionand careful positioning of the setting tool at the port. To ensuresufficient pressure is generated, it is typical to set these sleeves byapplying maximum pressure to the sleeve. However, there is a risk thatthe pressure could be high enough to rupture the sleeve.

Additionally, pressure must be sealed in the chamber to maintaininflation and, as the morphed sleeve may be needed for the life of thewell, keeping the pressure at a set value in the chamber is required.Leakage through trapped debris in the check valve at the port can causea slow loss of pressure. Temperature changes when the well is operatedcan cause pressure variations in the chamber. Consequently, though thesleeve has been plastically deformed and will therefore hold its newshape, if a sufficient pressure differential is created across thesleeve wall, there is a possibility that fracture or collapse can occurand the seal may be lost.

It is therefore an object of at least one embodiment of the presentinvention to provide a morphed isolation barrier which obviates ormitigates one or more disadvantages of the prior art.

It is a further object of at least one embodiment of the presentinvention to provide a method of creating an isolation barrier in a wellbore which obviates or mitigates one or more disadvantages of the priorart.

According to a first aspect of the present invention there is providedan assembly, comprising:

a tubular body arranged to be run in and secured within a largerdiameter generally cylindrical structure;a sleeve member positioned on the exterior of the tubular body andsealed thereto to create a chamber therebetween;the tubular body including a port to permit the flow of fluid into thechamber to cause the sleeve member to move outwardly and morph againstan inner surface of the larger diameter structure; and characterised inthat:a swellable material is located in at least a portion of the chamber;the swellable material being activated to swell by fluid entering thechamber and the swelled material supporting the morphed sleeve memberagainst the inner surface of the larger diameter structure.

In this way, the fluid pressure is not critical as it is used toactivate the swellable material, and the swelling material will itselfincrease fluid pressure in the chamber. By having the swellable materialcontained in the chamber, exposure to the activating fluid can becontrolled and there is no reliance on the swellable material to createthe seal. Additionally, once the sleeve is morphed the swellablematerial supports the sleeve in the morphed position.

The term “swellable” and similar terms (such as “swelling”) are usedherein to indicate an increase in volume of a material. Typically, thisincrease in volume is due to absorption or diffusion of molecularcomponents of the fluid into the material itself, but other swellingmechanisms or techniques may be used, if desired. Note that swelling isnot the same as expanding, although a material may expand as a result ofswelling.

The large diameter structure may be an open hole borehole, a boreholelined with a casing or liner string which may be cemented in placedownhole, or may be a pipeline within which another smaller diametertubular section requires to be secured or centralised.

The tubular body is preferably located coaxially within the sleeve andis part of a tubular string used within a wellbore, run into an open orcased oil, gas or water well. Therefore the present invention allows acasing section or liner to be centralised within a borehole or anotherdownhole underground or above ground pipe by provision of a morphablesleeve member positioned around the casing or liner. Centralisationoccurs as the sleeve will expand radially outwardly at a uniform ratewith the application of pressure from the swellable material.Additionally, the present invention can be used to isolate one sectionof the downhole annulus from another section of the downhole annulus andthus can also be used to isolate one or more sections of downholeannulus from the production conduit.

Preferably the swellable material is a swellable elastomer. Theswellable material may be as known in the industry for swellablepackers. Alternatively, the swellable material may be any compositionwhich increases in volume on contact with a specified fluid e.g.bentonites such as sodium bentonite. The swellable material may be of atype which swells immediately on contact with the activating fluid.Alternatively, the swellable material may swell following apredetermined time after contact with the activating fluid.

The swellable material may be arranged as a sleeve around the body. Inthis way, the assembly is simple to construct as the morphable sleevewill locate over the swellable sleeve and contain it with the chamber.Alternatively, the swellable material may be a plurality of swellableelements. In this way, the swell rate can be increased due to theincreased contact area for the activating fluid. The swellable materialmay be attached to the exterior of the tubular body or may be free tomove within the chamber. The swellable elements may be shaped as balls,cubes, strips or granules′.

Preferably, there is a plurality of ports arranged through the tubularbody. In this way, activating fluid can reach the maximum amount ofswellable material in the quickest time. The ports may be arrangedcircumferentially around the body. The ports may be arrangedlongitudinally along the body. In an embodiment, one or more channelsare machined on the exterior of the tubular body at the chamber. Thechannels provide for fluid flow between the swellable material and thetubular body, increasing the potential contact surface area between thefluid and the swellable material.

The port may include a barrier. In this way, fluid is prevented fromentering the chamber until activation is required. The barrier may be arupture disc which allows fluid to flow through the port at apredetermined fluid pressure. Alternatively the barrier may be a valve.Preferably the valve is a one-way check valve. In this way, fluid isprevented from exiting the chamber. More preferably the valve is set toclose when the pressure in the chamber reaches a morphed pressure value.In this way, swelling can occur rapidly by the introduction of highpressure fluid in the knowledge that fluid flow will stop when themorphed pressure is reached. The valve preferably allows pressure to bebled off so that fluid trapped in the chamber will not increase inpressure if swelling is still continuing after the morphed pressurevalue is reached.

The morphed sleeve will have a chamber filled with swelled material andfluid. Swelling of the material will increase the pressure of the fluidand both will exert pressure to cause the sleeve member to moveoutwardly and morph against the inner surface of the larger diameterstructure.

According to a second aspect of the present invention there is provideda method of setting a morphed sleeve in a well bore, comprising thesteps:

-   (a) locating a sleeve member on the exterior of a tubular body and    sealing it thereto to create a chamber therebetween;-   (b) locating a swellable material in the chamber;-   (c) running the tubular body on a tubular member into a wellbore and    positioning the sleeve member at a desired location within a larger    diameter structure;-   (d) pumping fluid through the tubular member and through a port in    the tubular body to access the chamber;-   (e) activating the swellable material with the fluid to create    swelling of the material in the chamber;-   (f) causing the sleeve to move radially outwardly and morph against    an inner surface of the larger diameter structure; and-   (g) supporting the morphed sleeve via the swelled material.

In this way, a selective seal is created between the morphed sleeve andthe inner surface of the larger diameter structure, with the swellablematerial increasing the rate of expansion of the sleeve and supportingthe morphed sleeve once it is expanded.

The large diameter structure may be an open hole borehole, a boreholelined with a casing or liner string which may be cemented in placedownhole, or may be a pipeline within which another smaller diametertubular section requires to be secured or centralised.

Preferably, step (d) includes the step of pumping fluid through thetubular member and through multiple ports in the tubular body to accessthe chamber. This provides a faster acting time for the swellablematerial.

Preferably, the method includes the step of rupturing a disc at a valvein the port to allow fluid to enter the chamber when the pressurereaches a desired value. This allows selective and controlled activationof the swellable material.

Preferably, in step (e) activating the swellable material with the fluidcreates immediate swelling of the material in the chamber.Alternatively, in step (e) activating the swellable material with thefluid creates swelling of the material in the chamber after apredetermined time. By delaying the onset of swelling, contact of fluidto all surfaces of the swellable material can be achieved beforeswelling occurs. In this way, optimum swelling of the material occurs.

The method may include the steps of running in an activation fluiddelivery tool, creating a temporary seal above and below the port andinjecting fluid from the tool into the chamber via the port. Such anarrangement allows selective operation of the sleeve member if more thanone sleeve member is arranged in the well bore.

In the description that follows, the drawings are not necessarily toscale. Certain features of the invention may be shown exaggerated inscale or in somewhat schematic form, and some details of conventionalelements may not be shown in the interest of clarity and conciseness. Itis to be fully recognized that the different teachings of theembodiments discussed below may be employed separately or in anysuitable combination to produce the desired results.

Accordingly, the drawings and descriptions are to be regarded asillustrative in nature, and not as restrictive. Furthermore, theterminology and phraseology used herein is solely used for descriptivepurposes and should not be construed as limiting in scope. Language suchas “including,” “comprising,” “having,” “containing,” or “involving,”and variations thereof, is intended to be broad and encompass thesubject matter listed thereafter, equivalents, and additional subjectmatter not recited, and is not intended to exclude other additives,components, integers or steps. Likewise, the term “comprising” isconsidered synonymous with the terms “including” or “containing” forapplicable legal purposes.

All numerical values in this disclosure are understood as being modifiedby “about”. All singular forms of elements, or any other componentsdescribed herein including (without limitations) components of theapparatus are understood to include plural forms thereof.

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings of which:

FIG. 1 is a half cross-sectional view through an assembly according toan embodiment of the present invention;

FIG. 2 is a half cross-sectional view through the assembly of FIG. 1when the sleeve is morphed to an inner wall of a well bore; and

FIG. 3 is a schematic illustration of a sequence for setting two sleevemembers in an open borehole; FIG. 3a is a cross-sectional view of aliner provided with two sleeve members; FIG. 3b shows the liner in theborehole of FIG. 3a with an activation fluid delivery tool insertedtherein; and FIG. 3c is a cross-sectional view of the liner of FIGS. 3aand 3b with morphed sleeves and pressure balanced chambers, in use.

Reference is initially made to FIG. 1 of the drawings which illustratesan assembly, generally indicated by reference numeral 10, including atubular body 12, sleeve member 14, chamber 16, port 18 and swellablematerial, generally indicated by reference numeral 20, according to anembodiment of the present invention.

Tubular body 12 is a cylindrical tubular section having at a first end22, a first connector (not shown) and at an opposite end 26, a secondconnector (not shown) for connecting the body 12 into a tubing stringsuch as casing, liner or production tubing that is intended to bepermanently set or completed in a well bore. Body 12 includes athroughbore 30 which is co-linear with the throughbore of the string.The string may be a drill pipe or any other tubular string designed tobe run in a well bore.

A port 18 is provided through the side wall 34 of the body 12 to providea fluid passageway between the throughbore 30 and the outer surface 36of the body 12. While only a single port 18 is shown, it will beappreciated that a set of ports may be provided. These ports may beequidistantly spaced around the circumference of the body 12 and/or bearranged along the body between the first end 22 and the second end 26to access the chamber 16.

Tubular body 12 is located coaxially within a sleeve member 14. Sleevemember 14 is a steel cylinder being formed from typically 316L or Alloy28 grade steel but could be any other suitable grade of steel or anyother metal material or any other suitable material which undergoeselastic and plastic deformation. Ideally the material exhibits highductility i.e. high strain before failure. The sleeve member 14 isappreciably thin-walled of lower gauge than the tubing body 12 and ispreferably formed from a softer and/or more ductile material than thatused for the tool body 12. The sleeve member 14 may be provided with anon-uniform outer surface 40 such as ribbed, grooved or other keyedsurface in order to increase the effectiveness of the seal created bythe sleeve member 14 when secured within another casing section orborehole.

An elastomer or other deformable material may be bonded to the outersurface 40 of the sleeve 14; this may be as a single coating but ispreferably a multiple of bands with gaps therebetween. The bands orcoating may have a profile or profiles machined into them. The elastomerbands may be spaced such that when the sleeve 14 is being morphed thebands will contact the inside surface 82 of the open borehole 80 first.The sleeve member 14 will continue to expand outwards into the spacesbetween the bands, thereby causing a corrugated effect on the sleevemember 14. These corrugations provide a great advantage in that theyincrease the stiffness of the sleeve member 14, increase its resistanceto collapse forces and also improves annular sealing.

A first end 42 of the sleeve 14 is attached to a stop 44 machined in theouter surface 36 of the body 12. Attachment is via pressure-tightconnections to provide a seal. An O-ring seal (not shown) may also beprovided between the inner surface 46 of the sleeve 14 and the outersurface 36 of the body 12 to act as a secondary seal or backup to theseal provided by the welded connection at the stop 44. Attachment couldalso be by means of a mechanical clamp. It will be appreciated that thesleeve 14 need not be attached to the stop 44.

A second stop 48 is arranged at a second end 50 of the sleeve 14. Thesecond stop 48 may be clamped to the body 12 so that the sleeve 14 canbe slid onto the body 12 over the second end during assembly. A seal 52is provided at the outer surface 36 of the body 12 forward of the stop48 so that the seal 52 is between the sleeve 14 and the body 12. Thisprovides a sliding seal so that the end of the sleeve 14 is permitted tomove towards the first end, relative to the body 12. Thus when thesleeve member 14 is caused to move in the radially outward direction,this causes simultaneous movement of the sliding seal 52, which has theadvantage in that the thickness of the sleeve 14 is not further thinnedby the radially outwards expansion.

Stop 44 together with the inner surface 46 of the sleeve 14 and theouter surface 36 of the body 12, define a chamber 16. The port 18 isarranged to access the chamber 16 and permit fluid communication betweenthe throughbore 30 and the chamber 16.

Located within the chamber 16 is a swellable material 20. Swellablematerials are known with swellable elastomers being commonly used in theindustry. Compositions which increase in volume on contact with aspecified fluid e.g. bentonites are known. While the compound sodiumbentonite is more commonly used in drilling muds it may be used in thepresent application. While the swellable material 20 may be a swellableelastomer, any swellable material capable of swelling against the fluidpressures needed to morph the sleeve may be used. In this application,pressures in the region of 5,000 to 10,000 psi are required. Theswellable material may be of a type which swells immediately on contactwith an activating fluid. Alternatively, the swellable material mayswell after a predetermined time after contact with an activating fluid.The swellable material 20 can be selected to activate with any desiredfluid, but preferably will act with a known well fluid. In this way, theactivation fluid is readily available when the sleeve 14 is to bemorphed. Both hydrocarbon-based and water-based (including brine)activated swellable materials are known.

Swellable material 20 is provided as chips 24. The chips 24 are droppedinto the chamber 16 before the second end 50 of the sleeve is sealed tothe body 12. By providing the material 20 as chips 24 they are easy tolocate in the chamber 16 and provide a greater surface area for contactwith an activating fluid than a larger, single piece of material. Whilechips 24 are described, the material 20 may be of any shape such asballs, cubes, granules' or even strips arranged as rings around theouter surface 36 of the body 12. The swellable material 20 couldalternatively be a single tubular section arranged as a swellable sleevearound the body 12 between the outer surface 36 of the body 12 and theinner surface 46 of the sleeve 14. The swellable material does notrequire to be attached to the body 12 and/or the sleeve 14 as anycontact would limit the available surface area for activation. It shouldbe noted that the sleeve 14 is not a coating applied to a swellablepacker.

The swellable material 20 is activated by activation fluid entering thechamber 16 through the port 18. In the embodiment shown, the swellablematerial 20 is selected to swell after a predetermined time on contactwith the activation fluid. This time delay allows the fluid to fill thechamber 16, surrounding all the chips 24 and thereby making contact withthe entire surface area of swellable material 20 within the chamber 16.

The material 20 will swell by the process of absorption or diffusion ofthe activation fluid into the material 20. The process will continueuntil an equilibrium is reached between absorbed fluid and surroundingfluid. The initial unswollen volume of material 20 is thereforecalculated on the basis of the expected volume of the chamber oncemorphed to be filled with swollen material 20 of a volume sufficient tomaintain a desired pressure on the inner surface 46 of the sleeve 14.This is calculated from knowledge of the diameter of the body 12, theapproximate diameter of the borehole 80 at the sleeve 14, the length ofthe sleeve 14, the material and thickness of the sleeve 14 and theproperties of the swellable material 20. Ideally a majority of thevolume of the unexpanded chamber is filled with unswollen swellablematerial.

On swelling, the material 20 increases in volume and thus each chip 24will take up an increased volume of the chamber 16. The chips 24 willcontact each other and as the volume of the chamber 16 is initiallysized to be smaller than the volume of the swollen material 20, thechips 24 will exert a pressure both on the fluid and on the walls of thechamber 16. As the sleeve 14 is of a more ductile material than the body14, the sleeve 14 will be forced radially outwardly by the pressure fromthe swelling material 20 and the fluid in the chamber 16. The sleeve 14will be forced against the wall 82 of the well bore 80 and the outersurface 46 of the sleeve 14 will morph to the wall 82 with the contacttherebetween creating a seal. This seal will be an annular seal aroundthe assembly 10 and between the assembly 10 and the well bore 80. Thisis as illustrated in FIG. 2.

At the port 18 there is located a check valve 54. The check valve 54 isa one-way valve which only permits fluid to pass from the throughbore 30into the chamber 16. The check valve 54 can be made to close when thepressure within the chamber 16 reaches a predetermined level, this beingdefined as the morphed pressure value. Thus, when the pressure in thesleeve 14 reaches the morphed pressure value, which will occur rapidlyon swelling of the material 20, the valve 54 will close. As the morphedpressure value is not created by fluid pressure alone, a high fluidpressure can initially be used to fill the chamber 16, with the checkvalve 54 being set to close after a fixed amount of fluid has passedtherethrough. The amount of fluid can be calculated as that required totake up the volume of the chamber 16 which isn't taken up with unswollenmaterial 20 on deployment. It will be appreciated that the check valve54 may not be required as the swollen material 20 may take up the innervolume and wholly support the morphed sleeve 14.

Also arranged at the port 32 is a rupture disc 56. The rupture discisolates the swellable material 20 in the chamber 16 from fluids in thethroughbore during run-in of the string. The rupture disc 56 is rated toa desired pressure at which fluid access to the chamber is desired. Inthis way, the rupture disc 56 can be used to control when the setting ofthe sleeve 14 is to begin and prevent premature swelling of the material20. The disc 56 can be operated by increasing pressure in thethroughbore 30 with the pressure to rupture the disc being selected tobe greater than the fluid pressure required to activate any other toolsor functions in the well bore.

Reference will now be made to FIG. 3 of the drawings which provides anillustration of the method for setting a sleeve within a well boreaccording to an embodiment of the present invention. Like parts to thosein the earlier Figures have been given the same reference numerals toaid clarity.

In use, the assembly 10 is conveyed into the borehole by any suitablemeans, such as incorporating the assembly 10 into a casing or linerstring 76 or on an end of a drill pipe and running the string into thewellbore 78 until it reaches the location within the open borehole 80 atwhich operation of the assembly 10 is intended. This location isnormally within the borehole at a position where the sleeve 14 is to beexpanded in order to, for example, isolate the section of borehole 80 blocated above the sleeve 14 from that below 80 d in order to provide anisolation barrier between the zones 80 b,80 d. Additionally a furtherassembly 10 b can be run on the same string 76 so that zonal isolationcan be performed in a zone 80 b in order that an injection, frac'ing orstimulation operation can be performed on the formation 80 b locatedbetween the two sleeves 14, 14 a. This is as illustrated in FIG. 3B.

Each sleeve 14,14 a can be set by increasing the pump pressure in thethroughbore 30 to a predetermined value which ruptures the disc 56giving fluid access to the chamber 16. Fluid entering the chamber 16activates the swellable material 20 which increases in volume creating apressure sufficient to cause the sleeve 14 to move radially away fromthe body 12 by elastic expansion, contact the surface 82 of the boreholeand morph to the surface 82 by plastic deformation.

Fluid may be pumped into the chamber 16 at any desired pressure as thethe material 20 can be set to swell before fluid pressure can exceedthat which would expand and rupture the sleeve 14. Indeed the checkvalve 54 can be set to allow a calculated volume of fluid to enter thechamber before closing. When closed, the check-valve will trap any fluidremaining in the chamber 16. However, as the material 20 will haveswollen to fill the volume of the morphed sleeve and still exertpressure on the sleeve 14, the material 20 will provide a support to thesleeve 14 and thus the presence of fluid to maintain a morphed fluidpressure value in the chamber is no longer required.

The sleeve 14 will have taken up a fixed shape under plastic deformationwith an inner surface 46 matching the profile of the surface 82 of theborehole 80, and an outer surface also matching the profile of thesurface 82 to provide a seal which effectively isolates the annulus 84of the borehole 80 above the sleeve 14 from the annulus 86 below thesleeve 14. If two sleeves 14,14 a are set together then zonal isolationcan be achieved for the annulus 84 between the sleeves 14,14 a. At thesame time the sleeves 14,14 b have effectively centered, secured andanchored the tubing string 76 to the borehole 80.

An alternative method of achieving morphing of the sleeve 14 is shown inFIG. 3B. This method uses an activation fluid delivery tool 88. Once thestring 76 reaches its intended location, tool 88 can be run into thestring 76 from surface by means of a coiled tubing 90 or other suitablemethod. The tool 88 is provided with upper and lower seal means 92,which are operable to radially expand to seal against the inner surface94 of the body 12 at a pair of spaced apart locations in order toisolate an internal portion of body 12 located between the seals 92; itshould be noted that said isolated portion includes the fluid port 18.Tool 88 is also provided with an aperture 96 in fluid communication withthe interior of the string 76.

To operate the tool 88, seal means 92 are actuated from the surface toisolate the portion of the tool body 12. Activation fluid is then pumpedunder pressure through the coiled tubing such that the pressurised fluidflows through tool aperture 96 and then via port 18 into chamber 16 andacts on the swellable material 20 in the same manner as describedhereinbefore. Use of such a tool allows setting of selective assemblies10 in a well bore.

A detailed description of the operation of such a fluid delivery tool 88is described in GB2398312 in relation to the packer tool 112 shown inFIG. 27 with suitable modifications thereto, where the seal means 92could be provided by suitably modified seal assemblies 214, 215 ofGB2398312, the disclosure of which is incorporated herein by reference.The entire disclosure of GB2398312 is incorporated herein by reference.

Using either pumping method, the increase in pressure of fluid and theswelling material directly against the sleeve 14 causes the sleeve 14 tomove radially outwardly and seal against a portion of the innercircumference of the borehole 80. The pressure within the chamber 16continues to increase such that the sleeve 14 initially experienceselastic expansion followed by plastic deformation. The sleeve 14 expandsradially outwardly beyond its yield point, undergoing plasticdeformation until the sleeve 14 morphs against the surface 82 of theborehole 80 as shown in FIG. 3C. Accordingly, the sleeve 14 has beenplastically deformed and morphed by pressure from the chamber contentswithout any mechanical expansion means being required.

Additionally, the fluid pressure is not critical as it is merely used toactivate the material; by having the swellable material contained in thechamber, exposure to the activating fluid can be controlled and there isno reliance on the swellable material to create the seal; and, once thesleeve is morphed the swellable material can support the sleeve in themorphed position.

The principle advantage of the present invention is that it provides anassembly for creating an isolation barrier in a well bore in which aswellable material is used to both decrease the reliance on fluidpressure to morph the sleeve and provide support to the morphed sleeveas a barrier.

A further advantage of the present invention is that it provides amethod for setting a sleeve in a well bore which uses well fluids toactivate a swellable material in a metal sleeve to gain the advantagesof a barrier of solid volume which can be used in corrosiveenvironments.

It will be apparent to those skilled in the art that modifications maybe made to the invention herein described without departing from thescope thereof. For example, while the swellable material is described asa solid it may be a liquid which solidifies when swollen.

We claim:
 1. An assembly, comprising: a tubular body arranged to be runin and secured within a larger diameter generally cylindrical structure;a sleeve member positioned on the exterior of the tubular body andsealed thereto to create a chamber therebetween; the tubular bodyincluding a port to permit the flow of fluid into the chamber to causethe sleeve member to move outwardly and morph against an inner surfaceof the larger diameter structure; and characterised in that: a swellablematerial is located in at least a portion of the chamber; the swellablematerial being activated to swell by fluid entering the chamber and theswelled material supporting the morphed sleeve member against the innersurface of the larger diameter structure.
 2. An assembly according toclaim 1 wherein the large diameter structure is selected from a groupcomprising: an open hole borehole, a borehole lined with a casing orliner string, a borehole lined with a casing or liner string which iscemented in place downhole, a pipeline within which another smallerdiameter tubular section requires to be secured or a pipeline withinwhich another smaller diameter tubular section requires to becentralised.
 3. An assembly according to claim 1 wherein the tubularbody is located coaxially within the sleeve and is part of a tubularstring used within a wellbore.
 4. An assembly according to claim 1wherein the swellable material is a swellable elastomer.
 5. An assemblyaccording to claim 1 wherein the swellable material is of a type whichswells immediately on contact with the activating fluid.
 6. An assemblyaccording to claim 1 wherein the swellable material is of a type whichswells following a predetermined time after contact with the activatingfluid.
 7. An assembly according to claim 1 wherein the swellablematerial is arranged as a sleeve around the body.
 8. An assemblyaccording to claim 1 wherein the swellable material is a plurality ofswellable elements.
 9. An assembly according to claim 8 wherein theswellable elements are shaped as balls, cubes, strips or granules'. 10.An assembly according to claim 1 wherein the swellable material isattached to the exterior of the tubular body.
 11. An assembly accordingto claim 1 wherein the swellable material is free to move within thechamber.
 12. An assembly according to claim 1 wherein there is aplurality of ports arranged through the tubular body.
 13. An assemblyaccording to claim 12 wherein the ports are arranged circumferentiallyaround the body.
 14. An assembly according to claim 12 wherein the portsare arranged longitudinally along the body.
 15. An assembly according toclaim 1 wherein one or more channels are machined on the exterior of thetubular body at the chamber.
 16. An assembly according to claim 1wherein the port includes a barrier.
 17. An assembly according to claim16 wherein the barrier is a rupture disc which allows fluid to flowthrough the port at a predetermined fluid pressure.
 18. An assemblyaccording to claim 16 wherein the barrier includes a valve.
 19. Anassembly according to claim 18 wherein the valve is a one-way checkvalve.
 20. (canceled)
 21. A method of setting a morphed sleeve in a wellbore, comprising the steps: (a) locating a sleeve member on the exteriorof a tubular body and sealing it thereto to create a chambertherebetween; (b) locating a swellable material in the chamber; (c)running the tubular body on a tubular member into a wellbore andpositioning the sleeve member at a desired location within a largerdiameter structure; (d) pumping fluid through the tubular member andthrough a port in the tubular body to access the chamber; (e) activatingthe swellable material with the fluid to create swelling of the materialin the chamber; (f) causing the sleeve to move radially outwardly andmorph against an inner surface of the larger diameter structure; and (g)supporting the morphed sleeve via the swelled material.
 22. (canceled)23. (canceled)
 24. (canceled)
 25. (canceled)
 26. (canceled) 27.(canceled)